Hydroxypropyl cellulose is a hydroxy ether which is obtained by reacting propylene oxide with cellulose. Hydroxypropyl cellulose is used as a binder or forming base material which is added to solid pharmaceutical preparations such as granules and tablets, as a binder for manufacturing ceramics, as a film or coating agent, or as a food additive, thickener, stabilizer, gelator, paste agent, emulsifier, dispersant, adhesive, and so on.
Hydroxypropyl cellulose is ordinarily supplied in particle form. As particulate hydroxypropyl cellulose, for example, Patent Document 1 discloses hydroxypropyl cellulose particles with a particle size of 1-150 μm for use in the adhesive layer of an adhesive patch. In addition, Patent Document 2 and Patent Document 3 record low substituted hydroxypropyl cellulose particles with a volume average particle size of 25 μm or less, measured by a dry laser diffraction method, for use in solid preparations.